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Eo-1 hyperion reflectance time series at calibration and validation sites: stability and sensitivity to seasonal dynamics
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Lagomasino, David Brunsell, Nathaniel A. Huemmrich, Karl Fred Middleton, Elizabeth M. Kokaly, Raymond F. Thome, Kurt J. Campbell, Petya K. Entcheva Novick, Kimberly A. |
| Copyright Year | 2013 |
| Description | This study evaluated Earth Observing 1 (EO-1) Hyperion reflectance time series at established calibration sites to assess the instrument stability and suitability for monitoring vegetation functional parameters. Our analysis using three pseudo-invariant calibration sites in North America indicated that the reflectance time series are devoid of apparent spectral trends and their stability consistently is within 2.5-5 percent throughout most of the spectral range spanning the 12-plus year data record. Using three vegetated sites instrumented with eddy covariance towers, the Hyperion reflectance time series were evaluated for their ability to determine important variables of ecosystem function. A number of narrowband and derivative vegetation indices (VI) closely described the seasonal profiles in vegetation function and ecosystem carbon exchange (e.g., net and gross ecosystem productivity) in three very different ecosystems, including a hardwood forest and tallgrass prairie in North America, and a Miombo woodland in Africa. Our results demonstrate the potential for scaling the carbon flux tower measurements to local and regional landscape levels. The VIs with stronger relationships to the CO2 parameters were derived using continuous reflectance spectra and included wavelengths associated with chlorophyll content and/or chlorophyll fluorescence. Since these indices cannot be calculated from broadband multispectral instrument data, the opportunity to exploit these spectrometer-based VIs in the future will depend on the launch of satellites such as EnMAP and HyspIRI. This study highlights the practical utility of space-borne spectrometers for characterization of the spectral stability and uniformity of the calibration sites in support of sensor cross-comparisons, and demonstrates the potential of narrowband VIs to track and spatially extend ecosystem functional status as well as carbon processes measured at flux towers. |
| File Size | 1593802 |
| Page Count | 15 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20140017180 |
| Archival Resource Key | ark:/13960/t5bc8zv0w |
| Language | English |
| Publisher Date | 2013-05-13 |
| Access Restriction | Open |
| Subject Keyword | Calibration Stability Eo-1 Evaluation Earth Observing System Eos Vegetative Index Time Series Analysis Calibrating Ecosystems Carbon Remote Sensing Spectral Reflectance Chlorophylls Narrowband Sensitivity Annual Variations Hyperion Vegetation Seasons Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
